Submission #494764

#	Time	Username	Problem	Language	Result	Execution time	Memory
494764		dannyboy20031204	Balanced Tree (info1cup18_balancedtree)	C++17	0 / 100	4075 ms	33208 KiB

balancedtree

#include <bits/stdc++.h>
#define ll long long
#define fi first
#define se second
#define mp make_pair 
using namespace std;
void db() {cout << endl;}
template <typename T, typename ...U> void db(T a, U ...b) {
    //return;
    cout << a << ' ', db(b...);
}
#ifdef Cloud
#define file freopen("input.txt", "r", stdin), freopen("output.txt", "w", stdout)
#else
#define file ios::sync_with_stdio(false); cin.tie(0)
#endif
const int N = 3001, inf = 1e9 + 1;
void solve(){
    int n;    
    cin >> n;
    vector<int> a(n);
    vector<int> g[n + 1];
    for (int i = 0; i < n - 1; i++){
        int u, v;
        cin >> u >> v;
        g[u].push_back(v);
        g[v].push_back(u);
    }
    for (int i = 0; i < n; i++) cin >> a[i];
    auto solve2 = [&](int _c, vector<int> c){
        queue<int> q;
        int dis[n + 1]{}, vis[n + 1]{}, mi[n + 1], par[n + 1]{};
        for (int &i : mi) i = inf;
        for (int i = 1; i <= n; i++) if (c[i - 1] == _c) {
            vis[i] = 1;
            par[i] = i;
            q.push(i);
        }
        while (!q.empty()){
            int u = q.front();
            q.pop();
            for (int i : g[u]){
                if (par[i] == par[u]) continue;
                if (vis[i]){
                    mi[par[u]] = min(mi[par[u]], dis[u] + dis[i] + 1);
                    mi[par[i]] = min(mi[par[i]], dis[u] + dis[i] + 1);
                }
                else{
                    dis[i] = dis[u] + 1;
                    vis[i] = 1;
                    par[i] = par[u];
                    q.push(i);
                }
            }
        }
        int ans = 0;
        for (int i = 1; i <= n; i++) if (par[i] == i) ans = max(ans, mi[i]);
        return ans;
    };
    int ans = inf, tar = 0;
    for (int i = 0; i < (1 << n); i++){
        vector<int> b;
        for (int j = 0; j < n; j++) b.push_back(i >> j & 1);
        bool imp = 0;
        for (int i = 0; i < n; i++){
            if(a[i] != b[i] and a[i] != -1) imp = 1;
        }
        if (imp) continue;
        int tmp = max(solve2(0, b), solve2(1, b));
        if (tmp < ans){
            ans = tmp;
            tar = i;
        }
    }
    if (ans >= n) return void(cout << -1 << '\n');
    cout << ans << '\n';
    for (int i = 0; i < n; i++) cout << (tar >> i & 1) << ' ';
    cout << '\n';
}
signed main(){
    file;
    int t;
    cin >> t;
    while (t--)
        solve();
}

• Subtask 1: 0 / 10
• Subtask 2: 0 / 13
• Subtask 3: 0 / 26
• Subtask 4: 0 / 45
• Subtask 5: 0 / 6